大家早，
在花了大部分时间研究如何限制我的模型创建之后，我终于找到了一个地方。嵌套语句现在向我显示未保存，这是个好消息。
但是我似乎无法让重定向或 flash[:base] 工作。下面是代码：
class SnippetsController < ApplicationController
before_filter :find_book
def create
if @snippet = @book.snippets.create!(params[:snippet])
redirect_to @book
else
flash[:base]
#render
end
end
def approve
#@snippet = @book.snippet.find(params[:id])
if @snippet.update_attribute(:approved, true)
redirect_to users_path
else
render root_path
end
end
def edit
@snippet = @book.snippets.find(params[:id])
end
def update
@snippet = @book.snippets.find(params[:id])
respond_to do |format|
if @snippet.update_attributes(params[:snippet])
format.html { redirect_to @book, notice: 'Comment was successfully updated.' }
else
format.html { render action: "edit" }
end
end
end
private
def find_book
@book = Book.find(params[:book_id])
end
end
模型父（书）
class Book < ActiveRecord::Base
has_many :snippets
attr_accessible :title, :book_id, :size
def snippets_limit_reached?
if size == 0
self.snippets.count >= 2
elsif size == 1
self.snippets.count >= 3
elsif size == 2
self.snippets.count >= 4
else
return false
end
end
end
孩子（片段）
class Snippet < ActiveRecord::Base
before_create :check_limit
belongs_to :book
attr_accessible :content, :book_id
validates :book_id, presence: true
def check_limit
if book.snippets_limit_reached?
errors.add :base, 'Snippet limit reached.'
return false
end
return true
end
end
如果您需要其他任何东西，请告诉我，仅供参考，当它运行时我无法通过嵌套创建！
if @snippet = @book.snippets.create!(params[:snippet])